<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Relevance</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REL="HOME"
TITLE="DataparkSearch Engine 4.53"
HREF="index.en.html"><LINK
REL="UP"
TITLE="Searching documents"
HREF="dpsearch-doingsearch.en.html"><LINK
REL="PREVIOUS"
TITLE="Designing search.html"
HREF="dpsearch-html.en.html"><LINK
REL="NEXT"
TITLE="Search queries tracking"
HREF="dpsearch-track.en.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="datapark.css"><META
NAME="Description"
CONTENT="DataparkSearch - Full Featured Web site Open Source Search Engine Software over the Internet and Intranet Web Sites Based on SQL Database. It is a Free search software covered by GNU license."><META
NAME="Keywords"
CONTENT="shareware, freeware, download, internet, unix, utilities, search engine, text retrieval, knowledge retrieval, text search, information retrieval, database search, mining, intranet, webserver, index, spider, filesearch, meta, free, open source, full-text, udmsearch, website, find, opensource, search, searching, software, udmsearch, engine, indexing, system, web, ftp, http, cgi, php, SQL, MySQL, database, php3, FreeBSD, Linux, Unix, DataparkSearch, MacOS X, Mac OS X, Windows, 2000, NT, 95, 98, GNU, GPL, url, grabbing"></HEAD
><BODY
CLASS="SECT1"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000C4"
VLINK="#1200B2"
ALINK="#C40000"
><!--#include virtual="body-before.html"--><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>DataparkSearch Engine 4.53: Reference manual</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="dpsearch-html.en.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 8. Searching documents</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="dpsearch-track.en.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="REL"
>8.5. Relevance</A
></H1
><A
NAME="AEN5540"
></A
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="REL-ORDER"
>8.5.1. Ordering documents</A
></H2
><P
><SPAN
CLASS="APPLICATION"
>DataparkSearch</SPAN
> by default sorts results first by <TT
CLASS="LITERAL"
>relevency</TT
>
and second by <TT
CLASS="LITERAL"
>popularity rank</TT
>.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RELEVANCY"
>8.5.2. Relevance calculation</A
></H2
><P
>In indexing, <SPAN
CLASS="APPLICATION"
>DataparkSearch</SPAN
> divides every document onto sections. A section is any part of the document, 
for example, for HTML documents this may be TITLE or META Description tag.</P
><P
>In addition to sections, some document factors are also take in account for relevance calculation: the average distance between
query words, the number of query word occurrences, the position of first occurrence of a query word, the difference between the
distribution of query word counts and the uniform distribution.</P
><P
>In searching, <SPAN
CLASS="APPLICATION"
>DataparkSearch</SPAN
> compares every document found against an "ideal" document. The "ideal"
document should have query words in every section defined and should have also the predefined values of additional factors.</P
><P
>Since sections definition located only in <TT
CLASS="FILENAME"
>indexer.conf</TT
> file, use
<A
NAME="AEN5557"
></A
> <B
CLASS="COMMAND"
>NumSections</B
>
command in <TT
CLASS="FILENAME"
>searchd.conf</TT
> or in <TT
CLASS="FILENAME"
>search.htm</TT
> to specify the number od section used.
By default, this value is 256. But note, <B
CLASS="COMMAND"
>NumSections</B
> do not affect document ordering, only the relevance value.</P
><DIV
CLASS="TABLE"
><A
NAME="AEN5564"
></A
><P
><B
>Table 8-3. Configure-time parameters to tune relevance calculation (switches for <B
CLASS="COMMAND"
>configure</B
>)</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><TBODY
><TR
><TD
><CODE
CLASS="OPTION"
>--enable-fullrel</CODE
></TD
><TD
><P
>This option enables full version of relevance calculation. Value by default: disabled (or fast relevance calculation).</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--disable-reldistance</CODE
></TD
><TD
><P
>This option disables accounting of average word distance for relevance calculation. Value by default: enabled.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--disable-relposition</CODE
></TD
><TD
><P
>This option disables accounting of first query word position for relevance calculation. Value by default: enabled.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--disable-relwrdcount</CODE
></TD
><TD
><P
>This option disables accounting of word counts for relevance calculation. Value by default: enabled.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-avgdist=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as the best average distance between words in document found.
Value by default: 464.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-bestpos=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as the best value of first word position in document found.
Value by default: 4.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-bestwrdcnt=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as the best number of each query word in document found. 
Value by default: 11.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-distfactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as a factor for average word distance for relevance calculation. 
Value by default: 0.2.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-lessdistfactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as factor of average word distance in relevance calculation when average
distance is less than value specified with <CODE
CLASS="OPTION"
>--with-avgdist</CODE
>.
Default value is <CODE
CLASS="OPTION"
>--with-distancefactor</CODE
> multiply by 2.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-posfactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as factor for difference between first query word position in document found and best position specified by <CODE
CLASS="OPTION"
>--with-bestpos</CODE
> option. 
Value by default: 0.5.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-lessposfactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify <CODE
CLASS="OPTION"
>NUM</CODE
> as factor of first word position in relevance calculation when it less than value
specified with <CODE
CLASS="OPTION"
>--with-bestpos</CODE
>.
Default value is <CODE
CLASS="OPTION"
>--with-posfactor</CODE
> multyply by 4.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-wrdcntfactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as factor for difference between count of query words in document found
and the best value specified by <CODE
CLASS="OPTION"
>--with-bestwrdcnt</CODE
> option. 
Value by default: 0.4.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-lesswrdcntfactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify <CODE
CLASS="OPTION"
>NUM</CODE
> as factor of word count in relevance calculation when this word count is less than
value specified with <CODE
CLASS="OPTION"
>--with-bestwrdcnt</CODE
>.
Default value is <CODE
CLASS="OPTION"
>--with-wrdcntfactor</CODE
> multiply by 10.</P
></TD
></TR
><TR
><TD
><CODE
CLASS="OPTION"
>--with-wrdunifactor=<CODE
CLASS="OPTION"
>NUM</CODE
></CODE
></TD
><TD
><P
>This option specify the <CODE
CLASS="OPTION"
>NUM</CODE
> as factor for difference of query word counts from uniform distribution. 
Value by default: 1.5.</P
></TD
></TR
></TBODY
></TABLE
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="REL-FULL"
>8.5.2.1. A full method of relevance calculation.</A
></H3
><A
NAME="AEN5669"
></A
><P
>Let <TT
CLASS="LITERAL"
>x</TT
> is the weighted sum of all sections. The weights for these sections are define by 
<CODE
CLASS="OPTION"
>wf</CODE
> parameter (see <A
HREF="dpsearch-doingsearch.en.html#SEARCH-CHANGEWEIGHT"
>Section 8.1.3</A
>&#62;). Let <TT
CLASS="LITERAL"
>y</TT
> is the weighted sum of
differences between values of additional factors of document found and corresponding values of additional factors of the "ideal"
document. And let <TT
CLASS="LITERAL"
>xy</TT
> is the weighted sum of sections where at least one query word has been found. Then value of
relevance for a document found is calculates as: <TT
CLASS="LITERAL"
>0.5 * ( x + xy ) / (x + y)</TT
>.</P
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="REL-FAST"
>8.5.2.2. A fast method of relevance calculation.</A
></H3
><A
NAME="AEN5682"
></A
><P
>Let <TT
CLASS="LITERAL"
>x</TT
> is the number of bits used in weighted values of all sections defined. Let <TT
CLASS="LITERAL"
>y</TT
> is
the weighted sum of differences between additional factors of document found and corresponding values of the "ideal" document.
And let <TT
CLASS="LITERAL"
>xy</TT
> is the number of bits where weighted values of sections of the "ideal" document are different to weighted
values of sections of document found. Then value of document relevance is calculates as: 
<TT
CLASS="LITERAL"
>( x - xy ) / ( x + y )</TT
>.</P
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="POPRANK"
>8.5.3. Popularity rank</A
></H2
><A
NAME="AEN5693"
></A
><P
><A
NAME="AEN5696"
></A
>
<SPAN
CLASS="APPLICATION"
>DataparkSearch</SPAN
> support two methods for popularity rank calculation. A method used in previous versions
called &quot;Goo&quot;, and new method is called &quot;Neo&quot;. By default, the <TT
CLASS="LITERAL"
>Goo</TT
> method is used. To select
desired PopRank calculation method use <B
CLASS="COMMAND"
>PopRankMethod</B
> command:
<PRE
CLASS="PROGRAMLISTING"
>PopRankMethod Neo</PRE
></P
><P
><A
NAME="AEN5704"
></A
>
You need enable links collection by <B
CLASS="COMMAND"
>CollectLinks yes</B
> command in your 
<TT
CLASS="FILENAME"
>indexer.conf</TT
> file for <TT
CLASS="LITERAL"
>Neo</TT
> method and for full functionality
of <TT
CLASS="LITERAL"
>Goo</TT
> method.
But this slow down a bit indexing speed. By default, links collection is not enabled. </P
><P
>By default, only intersite links (i.e. links from a page on 
one site to a page on an another site) are taken in account for the popularity rank calculation.
If you place
<B
CLASS="COMMAND"
><A
NAME="AEN5713"
></A
>PopRankSkipSameSite no</B
>
command in <TT
CLASS="FILENAME"
>indexer.conf</TT
> file, <B
CLASS="COMMAND"
>indexer</B
> take all links for this purpose.</P
><P
>You may assign initial value for page popularity rank using DP.PopRank META tag (see <A
HREF="dpsearch-htmlparser-meta.en.html"
>Section 4.3</A
>&#62;).</P
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="GOO-POPRANK"
>8.5.3.1. &quot;Goo&quot; popularity rank calculation method</A
></H3
><P
>The popularity rank calculation is made in two stages. At first stage, the value of <CODE
CLASS="OPTION"
>Weight</CODE
> parameter
for every server is divide by number of links from this server. Thus, the weight of one link from this server is calculated.
At second stage, for every page we find the sum of weights of all links pointed to this page. This sum is popularity rank for this page.</P
><P
><A
NAME="AEN5725"
></A
>
By default, the value of <CODE
CLASS="OPTION"
>Weight</CODE
> parameter is equal to 1 for all servers indexed.
You may change this value by <B
CLASS="COMMAND"
>Weight</B
> command in <TT
CLASS="FILENAME"
>indexer.conf</TT
> file or
directly in <TT
CLASS="LITERAL"
>server</TT
> table, if you load servers configuration from this table.</P
><P
>If you place
<CODE
CLASS="OPTION"
><A
NAME="AEN5734"
></A
>PopRankFeedBack yes</CODE
>
command in <TT
CLASS="FILENAME"
>indexer.conf</TT
> file, <B
CLASS="COMMAND"
>indexer</B
> will calculate site weights before page rank
calculation. To do that, <B
CLASS="COMMAND"
>indexer</B
> calculate sum of popularity rank for all pages from same site. If this sum will
great 1, the weight for site set to this sum, otherwise, site weight is set to 1.</P
><P
>If you place
<CODE
CLASS="OPTION"
><A
NAME="AEN5742"
></A
>PopRankUseTracking yes</CODE
>
command in <TT
CLASS="FILENAME"
>indexer.conf</TT
> file, <B
CLASS="COMMAND"
>indexer</B
> will calculate site weight as the number of 
tracked queries with restriction on this site.</P
><P
>If you place
<CODE
CLASS="OPTION"
><A
NAME="AEN5749"
></A
>PopRankUseShowCnt yes</CODE
>
command in <TT
CLASS="FILENAME"
>search.htm</TT
> (or <TT
CLASS="FILENAME"
>searchd.conf</TT
>) file, then for every result shown to user
corresponding <TT
CLASS="LITERAL"
>url.shows</TT
> value will be increased on 1, if relevance for this result is great or equal to
value specified by 
<CODE
CLASS="OPTION"
><A
NAME="AEN5756"
></A
>PopRankShowCntRatio</CODE
>
command (default value is 25.0).
If you place <CODE
CLASS="OPTION"
>PopRankUseShowCnt yes</CODE
> in <TT
CLASS="FILENAME"
>indexer.conf</TT
> file, <B
CLASS="COMMAND"
>indexer</B
>
will add to url's PopularityRank the value of <TT
CLASS="LITERAL"
>url.shows</TT
> multiplied by value, specified in
<CODE
CLASS="OPTION"
><A
NAME="AEN5764"
></A
>PopRankShowCntWeight</CODE
>
command (default value is 0.01).</P
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="NEO-POPRANK"
>8.5.3.2. &quot;Neo&quot; popularity rank calculation method</A
></H3
></DIV
><P
>For this method is supposed all pages are neurons and links between pages are links between neurons.
So it's possible use an error back-propagation algorithm to train this neural network. Popularity rank for a page is the 
activity level for corresponding neuron. See <A
HREF="http://www.maxime.net.ru/doc/Neo-en.pdf"
TARGET="_top"
>short description of The Neo 
Popularity Rank for web pages</A
>.</P
><P
>You may use
<CODE
CLASS="OPTION"
><A
NAME="AEN5773"
></A
>PopRankNeoIterations</CODE
>
command to specify the number of iterations of the Neo Popularity Rank calculation. Default value is 3.</P
><P
><A
NAME="AEN5777"
></A
>
By default, the Neo Popularity Rank is caclulated along with indexing. To speed up indexing, 
you may postpone Popularity Rank execution using <B
CLASS="COMMAND"
>PopRankPostpone</B
> command:</P
><PRE
CLASS="PROGRAMLISTING"
>PopRankPostpone yes</PRE
><P
>Then you may calculate the Neo Popularity Rank after indexing in same way as for method Goo, i.e.: 
<B
CLASS="COMMAND"
>indexer -TR</B
></P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="REL-BOOL"
>8.5.4. Boolean search</A
></H2
><A
NAME="AEN5786"
></A
><P
>Please note that in case of boolean searching for two or more
words, you have to enter operators (&amp;, |, ~, AND, OR, NOT, NEAR, ALL, etc.). I.e. it is necessary
to enter <KBD
CLASS="USERINPUT"
>a &amp; book</KBD
> instead of <KBD
CLASS="USERINPUT"
>a book</KBD
>.
See also <A
HREF="dpsearch-doingsearch.en.html#SEARCH-BOOL"
>Section 8.1.7</A
>&#62;.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="REL-CWORDS"
>8.5.5. Crosswords</A
></H2
><A
NAME="AEN5795"
></A
><A
NAME="AEN5797"
></A
><P
>This feature allows to assign words between
&lt;a href="xxx"&gt; and &lt;/a&gt; also to a document this link leads
to.  To enable Crosswords, please use
<B
CLASS="COMMAND"
>CrossWords yes</B
> command in
<TT
CLASS="FILENAME"
>indexer.conf</TT
> and
<TT
CLASS="FILENAME"
>search.htm</TT
>, and define <KBD
CLASS="USERINPUT"
>crosswords</KBD
> section in <TT
CLASS="FILENAME"
>sections.conf</TT
> file.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="SEA"
>8.5.6. The Summary Extraction Algorithm (SEA)</A
></H2
><A
NAME="AEN5807"
></A
><A
NAME="AEN5810"
></A
><A
NAME="AEN5813"
></A
><A
NAME="AEN5816"
></A
><P
><TT
CLASS="LITERAL"
>The Summary Exctraction Algorith (SEA)</TT
> builds the summary of three or more the most relevant sentences of the each
document indexed, if this document consists of six or more sentences. To enable this feature, add this command to your
<TT
CLASS="FILENAME"
>seaction.conf</TT
> file:
<PRE
CLASS="PROGRAMLISTING"
>Section sea x y</PRE
>
where <CODE
CLASS="OPTION"
>x</CODE
> - the number of section and <CODE
CLASS="OPTION"
>y</CODE
> - the maximum length of this section value, 
leave 0,  if you do not want show this in result pages.
If you specify <CODE
CLASS="OPTION"
>y</CODE
> non-zero, you may use <TT
CLASS="LITERAL"
>$(sea)</TT
> meta-variable in your search 
template to show the summary in result pages.</P
><P
>Related configuration directives:</P
><P
><A
NAME="AEN5829"
></A
>
The <B
CLASS="COMMAND"
>SEASentenceMinLength</B
> command specify the minimal length of sentence to be used in summary construction
using the SEA. Default value: 64.</P
><P
><A
NAME="AEN5834"
></A
>
The <B
CLASS="COMMAND"
>SEASentences</B
> command uses to specify the maximal number of sentences with length greater or equal to the value
specified by the <B
CLASS="COMMAND"
>SEASentenceMinLength</B
> command, which are used for summary construction in the SEA. Default value: 32.
Since the summary construction using SEA is nonlinear expensive (affects only indexing), 
you may adjust this value according to desired indexing performance.</P
><P
><A
NAME="AEN5840"
></A
>
With <B
CLASS="COMMAND"
>SEASections</B
> command you can specify the list of document sections which are used to construct SEA summary.
By default, only the "body" section is used for SEA summary construction.
<PRE
CLASS="PROGRAMLISTING"
>SEASections "body, title"</PRE
></P
><P
>This algorithm of automatic summary construction is based on ideas of Rada Mihalcea described in the paper 
<A
HREF="http://www.cs.unt.edu/~rada/papers/mihalcea.ijcnlp05.pdf"
TARGET="_top"
>Rada Mihalcea and Paul Tarau, 
An Algorithm for Language Independent Single and Multiple Document Summarization, 
in Proceedings of the International Joint Conference on Natural Language Processing (IJCNLP), Korea, October 2005</A
>.</P
><P
>Differences in DataparkSearch's SEA:</P
><P
></P
><UL
><LI
><P
>Initial weights for graph edges are calculates as a measure of similarity between 
3-gram distributions of corresponding sentences.</P
></LI
><LI
><P
>Initial value for all graph vertexes is equal to the value of 1 / (number of sentences + 1) in the current implementation.</P
></LI
><LI
><P
>The Neo PopRank algorithm is used as ranking algorithm to iterate values assigned to vertexes.</P
></LI
></UL
><P
>After indexing of document collection with this section defined, you may use $(sea) meta-variable in your 
template to show summary for a search result.</P
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="dpsearch-html.en.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.en.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="dpsearch-track.en.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Designing search.html</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="dpsearch-doingsearch.en.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Search queries tracking</TD
></TR
></TABLE
></DIV
><!--#include virtual="body-after.html"--></BODY
></HTML
>